如何在Unity使用Stripe API進行付款？

 public class StripeServices : IPaymentServices{
 
    //定義 Stripe API 的 Endpoint
    private string SessionRoute = "https://api.stripe.com/v1/checkout/sessions";
    
    private string SubscribeRoute = "https://api.stripe.com/v1/subscriptions";


    private string ApiKey = "sk_stripe_secret_key";
    private Action<object> sessionIdCallback;

    // 一開始使用的時候要把API Key帶進來
    public void Initialize(string key, Action<object> callback)
    {
        ApiKey = key;
        sessionIdCallback = callback;
    }

    // 一次性付款的時候呼叫
    public void Pay(object sessionModel)
    {
        var session = sessionModel as StripeSessionRequestModel;
        if (session == null)
        {
            Debug.Log("Session Info Is Null");
            return;
        }

        session.mode = "payment";
          
CoroutineManager.StartStaticCoroutine(CreateCheckoutSession(session));
    }
    

    // 訂閱模式
    public void Subscribe(object sessionModel)
    {
        var session = sessionModel as StripeSessionRequestModel;
        if (session == null)
        {
            Debug.Log("Session Info Is Null");
            return;
        }

        session.mode = "subscription";
        session.successUrl += "?type=vip&subscribeId=null";
        CoroutineManager.StartStaticCoroutine(CreateCheckoutSession(session));
    }

    // 取得付款狀況
    public void GetPaymentStatus(string sessionId, Action<object> callback)
    {
        CoroutineManager.StartStaticCoroutine(GetSessionStatus(sessionId, callback));
    }

    // 取得訂閱狀況
    public void GetSubscribeStatus(string subscribeId, Action<object> callback)
    {
        CoroutineManager.StartStaticCoroutine(GetSubscribeStatusCoroutine(subscribeId, callback));
    }

    // 取消訂閱
    public void Unsubscribe(string subscribeId)
    {
        CoroutineManager.StartStaticCoroutine(CancelSubscribeCoroutine(subscribeId,null));
    }


    // 使用Unity的 Webrequest 呼叫Stripe 的API
    private IEnumerator CreateCheckoutSession(StripeSessionRequestModel sessionModel)
    {
        var form = new WWWForm();
        form.AddField("mode", sessionModel.mode);
        form.AddField("customer_email", sessionModel.customerEmail);
        form.AddField("line_items[0][price]", sessionModel.priceId);
        form.AddField("line_items[0][quantity]", sessionModel.quantity);
        form.AddField("success_url", sessionModel.successUrl);
        form.AddField("cancel_url", sessionModel.cancelUrl);
        form.AddField("payment_method_types[0]", "card");

        using var www = UnityWebRequest.Post(SessionRoute, form);
        www.SetRequestHeader("Authorization", "Bearer " + ApiKey);
        www.SetRequestHeader("Content-Type", "application/x-www-form-urlencoded");
        yield return www.SendWebRequest();

        if (www.result != UnityWebRequest.Result.Success)
        {
            Debug.LogError("Stripe Call Error: " + www.error);
        }
        else
        {
            Debug.Log("Stripe Response: " + www.downloadHandler.text);
            var response = JsonConvert.DeserializeObject<StripeSessionResponseModel>(www.downloadHandler.text);
            sessionIdCallback?.Invoke(response.id);
            Application.OpenURL(response.url);
        }
    }
    
    private IEnumerator GetSessionStatus(string sessionId, Action<object> callback)
    {
        using var www = UnityWebRequest.Get(SessionRoute + $"/{sessionId}");
        www.SetRequestHeader("Authorization", "Bearer " + ApiKey);
        yield return www.SendWebRequest();
        if (www.result != UnityWebRequest.Result.Success)
        {
            Debug.LogError("Stripe Call Error: " + www.error);
        }
        else
        {
            Debug.Log("Stripe Response: " + www.downloadHandler.text);
            var response = JsonConvert.DeserializeObject<StripeSessionStatusModel>(www.downloadHandler.text);
            callback?.Invoke(response);
        }
    }
    
    private IEnumerator GetSubscribeStatusCoroutine(string subscribeId, Action<object> callback)
    {
        using var www = UnityWebRequest.Get(SessionRoute + $"/{subscribeId}");
        www.SetRequestHeader("Authorization", "Bearer " + ApiKey);
        yield return www.SendWebRequest();
        if (www.result != UnityWebRequest.Result.Success)
        {
            Debug.LogError("Stripe Call Error: " + www.error);
        }
        else
        {
            Debug.Log("Stripe Response: " + www.downloadHandler.text);
            var response = JsonConvert.DeserializeObject<StripeSubscribeStatusModel>(www.downloadHandler.text);
            callback?.Invoke(response);
        }
    }
    
    private IEnumerator CancelSubscribeCoroutine(string subscribeId, Action<object> callback)
    {
        using var www = UnityWebRequest.Delete(SubscribeRoute + $"/{subscribeId}");
        www.SetRequestHeader("Authorization", "Bearer " + ApiKey);
        yield return www.SendWebRequest();
        if (www.result != UnityWebRequest.Result.Success)
        {
            Debug.LogError("Stripe Call Error: " + www.error);
        }
        else
        {
            Debug.Log("Stripe Response: " + www.downloadHandler.text);
            var response = JsonConvert.DeserializeObject<StripeSubscribeStatusModel>(www.downloadHandler.text);
            callback?.Invoke(response);
        }
    }
}